Full adder arrays have been used to implement monolithic multipliers which give the product of two operands without the necessity of repetitively performing the operations of shifting and accumulating the intermediate results through an arithmetic logic unit.
However, the large adder arrays necessary to effect this type of multiplication (when placed on a single chip) increase the possibility that a single defect, originally in the substrate itself or arising through a processing anomally, will render the entire circuit useless.
In accordance with the preferred embodiment of the present invention a fault tolerant monolithic multiplier comprises a full adder array having at least one more row than functionally necessary. Ancillary gating and selection circuitry is provided to allow any row other than the first row to be deselected and the carry and sum logic signals for the deselected row and each subsequent row to be gated to the next row in line. Not including the first row as deselectable greatly simplifies the selection in gating logic required if the array size is a power of two as illustrated.